This invention relates to a tiedown apparatus or anchor, and more particularly to a composite anchor assembly which is especially useful in anchoring the ends of chains or cables used in straightening vehicle frames or the like. Although the anchor assembly is described in the context of its use in straightening frames, it can also be used in other applications requiring an anchor fixed to the ground, such as in anchoring heavy equipment to the floor, for example.
The present invention provides an improvement over the tiedown apparatus disclosed in my U.S. Pat. No. 3,494,587, which includes an outer shell disposed in an opening in a floor, a wedge member disposed in the shell, and a force-applying plate below the wedge. A short length of chain extends from a top cover plate to a point of attachment on the force-applying plate. A cable to be anchored is attached on the short length of chain. Tensioning of the cable pulls the force-applying plate upwardly to force the wedge member upwardly into the shell to expand the walls of the shell radially outwardly to embed the shell in the floor, providing a fixed anchor point for tension forces applied to the cable. This tiedown apparatus is especially useful when repairing frame damage to vehicles such as automobiles, in which one end of the vehicle frame is anchored by a chain or cable extending from the frame to the tiedown apparatus. A pulling force is applied to the opposite end of the frame against the resistance provided by the anchored cable or chain.
The present invention is based on a recognition that the tiedown apparatus disclosed in my patent has several disadvantages even though the tiedown apparatus, in recent years, has been adopted throughout the vehicle body repair industry.
For example, the wedge member is virtually impossible to remove once wedged in place in the outer shell. This make it virtually impossible to also remove the short length of chain and its attachment plate from the shell. The tiedown apparatus is prone to filling up with dirt and other corrosive matter which are difficult to remove from the shell. Since the chain and its force-applying plate cannot be easily removed from the shell, it is difficult to gain access to the interior of the shell to remove dirt. If the tiedown apparatus has been in place for a relatively long time, the wedge corrodes and often requires a cutting torch to remove the wedge from the shell so that the chain and its force-applying plate can be removed. Alternately, the outer shell must be removed by chipping away the concrete around the tiedown apparatus.
If the chain and its force-applying plate are not removed periodically, then the chain rusts and eventually breaks under the pulling forces applied to it. The inability to remove the chain also makes it virtually impossible to interchange chains of different weight with the tiedown apparatus. Thus, several tiedown devices of different sizes are commonly used to accommodate chains of different weight.
The structure of the patented tiedown apparatus also causes the tensioned chain to crush portions of the concrete floor surrounding the outer shell.
The present invention provides an anchor which overcomes the disadvantages of the patented tiedown apparatus described above. The present invention also is an improvement over tiedown apparatus disclosed in the following patents:
______________________________________ U.S. Pat. No. Patentee ______________________________________ 1,102,079 Rizer 2,120,577 Schulte 3,106,377 Cotton 3,124,385 Neptune 3,201,166 Boutin 3,367,620 Holt 3,404,504 Taylor 3,494,587 Kuhn 3,550,343 Buske 3,990,207 Eck et al 3,992,919 Jarman Foreign Patents Brit. 139,751 Wagner Fr. 1,560,445 Bohan ______________________________________